220v转12v阻容降压电路详解
2020-06-01 15:05阅读：
220v转12v采用电容降压时应注意以下几点：
1、根据负载的电流大小
和交流电
zhi的工作频率选取适当的电容，而不是依据负载的电压和功率。
2、限流电容必须采用无极性电容，绝对不能采用电解电容。
dao而且电容
的耐压须在400V以上。最理想的电容为铁壳油浸电容。
3、电容降压不能用于大
版功率负载，因为不安全。
4、电容降压不适合动态负载。
5、同样，电容降压不适合容性和感性负载。
6、当需要直流工作时，尽量采用半波整流。不建议采用桥式整
流，
因为全波整流产生浮置的地，并在零
线和权火线之间产生高压，造成人体触电伤害。
220v转12v阻容降压电路详解：
通过降压电容C1向负载提供的电流Io，实际上是流过C1的充放电电流Ic。C1容量越大，容抗Xc越小，则流经C1的充、bai放电电流越大。当负载电流Io小于C1的充放电电流时，多余的电流就会流过稳压管，若稳压管的最大允 du许电流Idmax小于Ic-Io时易造成稳压管烧毁。
The current Io provided to the load
through the buck capacitor C1 is actually the charge and discharge
current Ic flowing through C1. The larger the capacity of C1 and
the smaller the capacitive reactance Xc, the larger the charging
and discharging current flowing through C1. When the load current
Io is less than the charge and discharge current of C1, excess
current will flow through the voltage regulator tube. If the
maximum allowable current Idmax of the voltage regulator tube is
less than Ic-Io, the voltage regulator tube will be easily
burned.
Pay attention to the following points
when using capacitor voltage reduction from 220v to
12v:
1. Choose the appropriate capacitor
according to the current size of the load and the operating
frequency of the AC power, rather than the voltage and power of the
load.
2. Current-limiting capacitors must use
non-polarized capacitors, and electrolytic capacitors must never be
used. dao and the withstand voltage of the capacitor must be above
400V. The most ideal capacitor is an iron-immersed
capacitor.
3. Capacitor buck can not be used for
large-scale power load, because it is not safe.
4. Capacitor voltage reduction is not
suitable for dynamic loads.
5. Similarly, capacitive buck is not
suitable for capacitive and inductive loads.
6. When DC work is required, try to use
half-wave rectification. Bridge rectification is not recommended
because full-wave rectification creates a floating ground and
generates a high voltage between the neutral line and the right
fire line, causing electric shock to the human
body.
